Submission #213280

# Submission time Handle Problem Language Result Execution time Memory
213280 2020-03-25T12:07:44 Z someone_aa Split the sequence (APIO14_sequence) C++17
71 / 100
2000 ms 59768 KB
#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
#define ld long double
#define pll pair<ll,ll>
using namespace std;
const ld inf = 1e18;
const ll infll = 1e18;
const int maxn = 100100;
ll arr[maxn], pref[maxn];
ll dp[210][maxn], n, k;
ll parent[210][maxn];

struct cht {
	struct line {
		ll k, b; ld x;
		ll val; bool isquery;
		ll ind;

		line (ll _k=0LL, ll _b=0LL, ll _ind=0) :
			k(_k), b(_b), x(-inf), val(0), isquery(false), ind(_ind) { }

		ll eval(ll x) const { return k*x+b; }
		bool parallel(const line &l) const { return k == l.k; }
		ld intersection(const line &l) const {
			if(parallel(l)) return inf;
			return (1.0*b - l.b) / (1.0*l.k - k);
		}

		bool operator <(const line &l) const {
			if(l.isquery) return  x < l.val;
			else return k < l.k;
		}
	};

	set<line>hull;
	typedef set<line>::iterator iter;

	bool cPrev(iter it) { return it != hull.begin(); }
	bool cNext(iter it) { return it != hull.end() && next(it) != hull.end(); }

	bool bad(const line &l1, const line &l2, const line &l3) {
		return l1.intersection(l3) <= l1.intersection(l2);
	}
	bool bad(iter it) {
		return cPrev(it) && cNext(it) && bad(*prev(it), *it, *next(it));
	}

	iter update(iter it) {
		if(!cPrev(it)) return it;

		line tmp(*it);
		ld x = tmp.intersection(*prev(it));
		tmp.x = x;

		it = hull.erase(it);
		return hull.insert(it, tmp);
	}
	void addline(ll k, ll b, ll ind) {
		line l(k, b, ind);
		iter it = hull.lower_bound(l);

		if(it != hull.end() && it->parallel(l)) {
			if(b > it->b) it = hull.erase(it);
			else return;
		}

		it = hull.insert(it, l);
		if(bad(it)) return (void) hull.erase(it);

		while(cPrev(it) && bad(prev(it))) hull.erase(prev(it));
		while(cNext(it) && bad(next(it))) hull.erase(next(it));

		it = update(it);
		if(cPrev(it)) update(prev(it));
		if(cNext(it)) update(next(it));
	}

	pll query(ll x) {
		if(hull.empty()) return mp(-infll, -1LL);

		line tmp;
		tmp.val = x; tmp.isquery = true;
		iter it = --hull.lower_bound(tmp);

		return mp(it->eval(x), it->ind);
	}
};

int main() {
	cin>>n>>k;
	for(int i=1;i<=n;i++) {
		cin>>arr[i];
		pref[i] = pref[i-1] + arr[i];
	}

	for(int d=1;d<=k;d++) {
		if(d == 1) {
			for(int i=1;i<n;i++) {
				dp[d][i] = pref[i] * (pref[n] - pref[i]);
			}
			continue;
		}

		cht ds;
		for(int i=d;i<n;i++) {
			// add info for state(d-1, i-1)
			ds.addline(pref[i-1], dp[d-1][i-1] - pref[i-1]*pref[n], i-1);
			pll curr = ds.query(pref[i]);
			dp[d][i] = curr.first + pref[i]*pref[n] - pref[i] * pref[i]; 
			parent[d][i] = curr.second;
		}
	}

	ll result = -inf;
	ll resultind = -1;
	for(int i=k;i<n;i++) {
		if(dp[k][i] > result) {
			result = dp[k][i];
			resultind = i;
		}
	}
	cout<<result<<"\n";
	vector<int>v;
	for(int i=k;i>=1;i--) {
		v.pb(resultind);
		resultind = parent[i][resultind];
	}
	reverse(v.begin(), v.end());
	for(int i:v) {
		cout<<i<<" ";
	} cout<<"\n";
}
# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB contestant found the optimal answer: 108 == 108
2 Correct 5 ms 384 KB contestant found the optimal answer: 999 == 999
3 Correct 5 ms 384 KB contestant found the optimal answer: 0 == 0
4 Correct 5 ms 384 KB contestant found the optimal answer: 1542524 == 1542524
5 Correct 5 ms 512 KB contestant found the optimal answer: 4500000000 == 4500000000
6 Correct 5 ms 384 KB contestant found the optimal answer: 1 == 1
7 Correct 5 ms 384 KB contestant found the optimal answer: 1 == 1
8 Correct 5 ms 384 KB contestant found the optimal answer: 1 == 1
9 Correct 5 ms 384 KB contestant found the optimal answer: 100400096 == 100400096
10 Correct 5 ms 384 KB contestant found the optimal answer: 900320000 == 900320000
11 Correct 5 ms 384 KB contestant found the optimal answer: 3698080248 == 3698080248
12 Correct 5 ms 384 KB contestant found the optimal answer: 3200320000 == 3200320000
13 Correct 5 ms 384 KB contestant found the optimal answer: 140072 == 140072
14 Correct 5 ms 384 KB contestant found the optimal answer: 376041456 == 376041456
15 Correct 5 ms 384 KB contestant found the optimal answer: 805 == 805
16 Correct 5 ms 384 KB contestant found the optimal answer: 900189994 == 900189994
17 Correct 5 ms 384 KB contestant found the optimal answer: 999919994 == 999919994
# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB contestant found the optimal answer: 1093956 == 1093956
2 Correct 5 ms 384 KB contestant found the optimal answer: 302460000 == 302460000
3 Correct 5 ms 896 KB contestant found the optimal answer: 122453454361 == 122453454361
4 Correct 5 ms 384 KB contestant found the optimal answer: 93663683509 == 93663683509
5 Correct 5 ms 512 KB contestant found the optimal answer: 1005304678 == 1005304678
6 Correct 5 ms 384 KB contestant found the optimal answer: 933702 == 933702
7 Correct 5 ms 640 KB contestant found the optimal answer: 25082842857 == 25082842857
8 Correct 5 ms 512 KB contestant found the optimal answer: 687136 == 687136
9 Correct 6 ms 384 KB contestant found the optimal answer: 27295930079 == 27295930079
10 Correct 5 ms 512 KB contestant found the optimal answer: 29000419931 == 29000419931
# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB contestant found the optimal answer: 610590000 == 610590000
2 Correct 5 ms 384 KB contestant found the optimal answer: 311760000 == 311760000
3 Correct 17 ms 2816 KB contestant found the optimal answer: 1989216017013 == 1989216017013
4 Correct 5 ms 384 KB contestant found the optimal answer: 1499437552673 == 1499437552673
5 Correct 11 ms 2176 KB contestant found the optimal answer: 1019625819 == 1019625819
6 Correct 11 ms 2688 KB contestant found the optimal answer: 107630884 == 107630884
7 Correct 13 ms 2944 KB contestant found the optimal answer: 475357671774 == 475357671774
8 Correct 8 ms 1152 KB contestant found the optimal answer: 193556962 == 193556962
9 Correct 6 ms 768 KB contestant found the optimal answer: 482389919803 == 482389919803
10 Correct 9 ms 1280 KB contestant found the optimal answer: 490686959791 == 490686959791
# Verdict Execution time Memory Grader output
1 Correct 6 ms 640 KB contestant found the optimal answer: 21503404 == 21503404
2 Correct 6 ms 512 KB contestant found the optimal answer: 140412195 == 140412195
3 Correct 75 ms 5496 KB contestant found the optimal answer: 49729674225461 == 49729674225461
4 Correct 6 ms 640 KB contestant found the optimal answer: 37485571387523 == 37485571387523
5 Correct 65 ms 5496 KB contestant found the optimal answer: 679388326 == 679388326
6 Correct 58 ms 4728 KB contestant found the optimal answer: 4699030287 == 4699030287
7 Correct 76 ms 5496 KB contestant found the optimal answer: 12418819758185 == 12418819758185
8 Correct 75 ms 5368 KB contestant found the optimal answer: 31093317350 == 31093317350
9 Correct 20 ms 1536 KB contestant found the optimal answer: 12194625429236 == 12194625429236
10 Correct 34 ms 2552 KB contestant found the optimal answer: 12345131038664 == 12345131038664
# Verdict Execution time Memory Grader output
1 Correct 16 ms 1792 KB contestant found the optimal answer: 1818678304 == 1818678304
2 Correct 15 ms 1792 KB contestant found the optimal answer: 1326260195 == 1326260195
3 Correct 947 ms 34680 KB contestant found the optimal answer: 4973126687469639 == 4973126687469639
4 Correct 21 ms 2048 KB contestant found the optimal answer: 3748491676694116 == 3748491676694116
5 Correct 465 ms 21356 KB contestant found the optimal answer: 1085432199 == 1085432199
6 Correct 530 ms 24568 KB contestant found the optimal answer: 514790755404 == 514790755404
7 Correct 675 ms 26488 KB contestant found the optimal answer: 1256105310476641 == 1256105310476641
8 Correct 578 ms 21880 KB contestant found the optimal answer: 3099592898816 == 3099592898816
9 Correct 592 ms 24696 KB contestant found the optimal answer: 1241131419367412 == 1241131419367412
10 Correct 761 ms 31356 KB contestant found the optimal answer: 1243084101967798 == 1243084101967798
# Verdict Execution time Memory Grader output
1 Correct 149 ms 14840 KB contestant found the optimal answer: 19795776960 == 19795776960
2 Correct 156 ms 14840 KB contestant found the optimal answer: 19874432173 == 19874432173
3 Execution timed out 2101 ms 59768 KB Time limit exceeded
4 Halted 0 ms 0 KB -